Sprayers and dispensers for mixing and dispensing liquids into a carrier fluid, such as water, are disclosed in U.S. Pat. Nos. 5,152,461; 5,320,288; 5,385,270; 5,398,846; 5,402,916; 5,595,345; 5,605,578; and 5,713,519. Such sprayers typically include an inlet for a hose, such as a garden hose, and an inlet for a siphon tube for removing products from a container attached to the sprayer. The sprayers and dispensers typically spray a water/product mixture, or water only, through one or more horizontally or vertically arranged outlets of the sprayer.
Some sprayers or dispensers that include a positive "trigger" pump include two separate containers of product(s) for dispensing those product(s) from the sprayer, but do not have any means of connection to a carrier fluid for instantaneous dilution and the products dispensed must be diluted at the factory to ready-to-use concentration so a high percentage of weight and volume formulated is water, thereby causing users to buy four to fifty times more weight and volume of finished goods than they would otherwise need to achieve the same kind of uniform and broad coverage. Also, these sprayers cannot be used comfortably to treat anything but the smallest surface areas. These prior art sprayers and dispensers are often difficult to assemble and to use and do not always dispense product as desired or ergonomically. Furthermore, with some sprayers it is difficult or impossible to control product dilution ratios and to provide relatively large or small dilution ratios at relatively low flow rates. For those prior art sprayers that use a venturi to draw product into a flowing stream of diluent, in order to achieve relatively low dilution ratios, it is necessary to employ relatively high flow rates.
In conventional sprayers that use an aspirator to draw fluid from a container into a flowing stream of diluting fluid, there is a requirement that the outlet passage be of greater diameter than the inlet passage so as to produce a low pressure area within the portion of greater diameter. U.S. Pat. No. 5,595,345 specifically teaches that in an aspirated system, the downstream portion must have a larger cross-sectional area than the upstream portion. These design parameters however limit the ability to provide a wide range of dilution ratios at widely varying flow rates and to provide fixed dilution ratios that are independent of bulk fluid flow.
Thus, a need exists for a sprayer that dispenses a multiple-part concentrated product efficiently and effectively, is relatively easy to assemble and use, has variable dilution ratios and also can achieve a relatively wide range of dilution ratios at relatively low flow rates. Furthermore, there is a need for a dispenser that can sequentially dispense separate components or multiple components incompatible upon storage or can dispense the same component at different dilution ratios. Additionally, there is a need for an apparatus that can dispense or reintroduce to a diluent stream components that were removed or inadvertently filtered from a primary product stream or to introduce additional therapeutic components.